DNA methylation beta values at 37,488 CpG sites for beluga whales collected in Cook Inlet, Alaska, between 1992 and 2018

A custom DNA methylation array was used to measure methylation levels at 37,488 cytosine-guanine sites (CpGs) in the beluga genome using a calibration dataset of deceased beluga whales with estimated chronological ages (n=69) using tooth growth layers. Data were generated on a bead array using Illumina Infinium technology. IDAT files (with measures of fluorescence from the iScan machine) were produced and normalized data were uploaded here. Data were normalized using the SeSAMe pipeline (Zhou et al., 2018). Date files are uploaded for (1) the epigenetic clock calibration dataset and (2) a dataset of whales of unkown age, or the "biopsy dataset." The calibration dataset is for whales that have chronological ages derived from tooth growth layer group counts. The biopsy dataset consists of whales of unknown age that are living in Cook Inlet and were sampled by biopsy dart in 2016-2018. All samples were of skin tissue. Data here includes (1) beta values for each sample for each probe on the array and (2) detection p-values describing the confidence in those beta values.

本研究采用定制化DNA甲基化芯片（custom DNA methylation array），依托基于牙齿生长层估算实龄的死亡白鲸校正数据集（样本量n=69），对白鲸基因组内37488个胞嘧啶-鸟嘌呤位点（CpGs，cytosine-guanine sites）的甲基化水平进行定量检测。实验依托Illumina Infinium技术在微珠阵列（bead array）上完成数据产出，生成了搭载iScan扫描仪荧光检测数据的IDAT文件，并将标准化处理后的数据上传至本数据集。数据标准化流程采用SeSAMe分析管线（Zhou等，2018）。本次上传的数据分为两类：(1) 表观遗传时钟校正数据集；(2) 未知年龄白鲸的“活检数据集”。其中校正数据集的样本均通过牙齿生长层组计数获得确切实龄；活检数据集的样本为2016-2018年间通过活检镖取样、栖息于库克湾（Cook Inlet）的活体未知年龄白鲸，所有样本均取自皮肤组织。本数据集包含两项核心数据内容：(1) 芯片上每个探针对应各样本的β值；(2) 用于表征上述β值检测置信度的检测p值。